This invention relates to improved techniques and apparatus for new installation or replacement of underground pipelines, gas mains, water and sewer lines and other service and utility conduits. The apparatus and method are for creating a tunnel to accommodate new piping, inserting the new piping, and doing so without the need to excavate the tunnel or excavate or enlarge any man-hole or utility vault along the line or to create large openings at the destination location. The apparatus can work with a pilot hole or with preexisting pipe. The original pipe can be any fracturable material. Also the apparatus and method allows for substantial enlargement of preexisting line opening and the subsequent or simultaneous use of a multitude of different types of piping materials, thus meeting the needs of utility companies like water providers to use standard materials for the use of their district.
The underground location of lines and conduit for the many utilities in service today means that replacement of existing lines with new conduit lines is more complicated and necessitated due to age and deterioration, accidental breaks or population and usage growth making existing lines obsolete. Often the lines were installed with open trenches many years ago and subsequently new developments, such as roads, housing or landscaping have gone in over the surface, thus making re-excavation impossible or unacceptable. Also excavation methods are expensive in man power, equipment and risk of injury or damage.
There are numerous methods in use and available to replace old or outdated lines with new line material and without extensive excavation, but each has a variety of drawbacks or limitations. The commonly used method to replace pipe without excavation of which this invention is an improvement is called pipe bursting. Streatfield, U.S. Pat. No. 4,738,565 is one such method. It makes use of a conical shaped mole that is forced through an existing pipe and, in turn, pulls the new piping into the space. The bursting occurs when the mole is forced into the pipe. The mole is shaped such that it is smaller than the inside diameter of the old pipe at one end of the mole and larger than the inside diameter of the pipe at the other end of the mole and thus causes the original pipe to be fractured or, by other methods, cut. The object is to destroy and displace or remove the original pipe structure to then allow the new replacement pipe""s structure to take the place of the original. Thus the new pipe replaces the old pipe without excavating along the entire length of the pipe being replaced.
The methods, such as the above, however, generally require that two excavations be madexe2x80x94one at the start of the pipe bursting and the second at the end. This then accomplishes the replacement in that section. If more than one section is to be replaced, then successive points of excavation are made to accommodate the equipment and tools used to force the mole to do its job. For the mole tool to be started in the correct manner at the start of the hole a large excavation is necessary and another large excavation is needed to allow the mole tool to be removed at the end joint. Most of the current methods make use of equipment and tools that require the end point to be excavated even if there is access through a manhole vault at the location because the removal of the tool at the end requires a larger opening than the manhole vault. This causes problems as the manholes themselves are expensive structures to replace. Usually a manhole vault is in the system and often is located in a roadway. The previous methods require excavation of the manhole or vault which means that the excavation will impede traffic while the excavation is made, used and finally replaced and repaired. The necessity to excavate in streets is often regulated by local government to prevent an unacceptable number or timing of street cuts. Thus construction projects may have to be delayed for city permits.
Boring machines are often used to create holes in soil without the necessity of digging trenches. These can be with ram like action such as percussive devices. See Chepurnoi, U.S. Pat. No. 3,952,813, where a hammer drives a pointed end piece through the soil. Also it is known to drive a hollow pipe through the soil, then evacuate the pipe to leave the pipe available for various uses. Alternately the bore may be created by a drilling head that drills the hole.
There are numerous methods to burst an existing pipe to be replaced by a new pipe, done in a single operation. These methods and apparatus use drill or cutting heads with hammer-like driving forces used to move the head and pull the replacement pipe into the newly created hole. These include Parish, U.S. Pat. No. 5,628,585, where the replacement pipe is polyorefin and the old pipe is cut, chipped and ground away by roller bits worked by a drive shaft, and also Granella, U.S. Pat. No. 5,403,122.
The use of pulling means to draw the bursting tool and new pipe is used in Gherrington, U.S. Pat. No. 5,456,552, Luksch, U.S. Pat. No. 5,076,731, Torielli, U.S. Pat. No, 5,192,165, and Moriarty, U.S. Pat. No. 5,302,053.
Alternately, the bursting tool and pipe may be driven by a hammer that fits inside the pipe such as in Fisk, Re 35,271 and Re 35,542, and Kayes, U.S. Pat. No. 5,480,263, and Streatfield, U.S. Pat. No. 4,738,565 which also alternatively uses a pulling method.
Some methods make use of ramming force exerted at the bursting head through a hydraulic or pneumatic force applied inside the piping. As the head advances new sections of pipe are added and pushed forwardxe2x80x94not as the force to move the head but merely to advance the new pipe in conjunction with the head. See, Tenbusch, U.S. Pat. No. 5,482,404.
All of the above methods have deficiencies. None address the issues of pipe bursting into a confined location to avoid having extensive and expensive excavation at the exit point or the ability to increase the size of the pipe substantially.
The present invention, techniques and apparatus are disclosed for installing new pipe or replacing old pipe with new pipe of the same or larger diameter, in such a manner as to be able to do the installation without trenching and also allowing the installation to be to a vault or man hole without the necessity of destroying the man hole or vault, or excavating a large hole at the man hole location.
The features of the present invention allows for forces being applied from the rear as in a ramming force, from the front as in a pulling force or a combination of these, all dependent upon the circumstances to be dealt with. The apparatus has a bursting ram that breaks up the old pipe or enters a pilot hole and expands the opening to the required size equaling the size of the new pipe. The tubular casing is installed and inserted in the new opening at the same time. The bursting ram has a fracturing mandrel. It can have a front opening that is fitted with a floating eye. When being pulled the floating eye covers the front opening. A cap may cover the floating eye. At the end of the job the floating eye is released allowing the front opening to be opened for access to the interior of the bursting ram for disassembly of the apparatus.
As the preferred embodiment of this improved fracturing mandrel, the T assembly with a connecting eye extends from the forward aperture of the fracturing mandrel. The T piece extends from the rear aperture of the fracturing mandrel. The T assembly is removably attached to a structure piece in the casing, expansion mandrel or a connecting carrier ring to form a connection of the fracturing mandrel and the next piece.
In some circumstances the fracturing mandrel is attached to the casing. In other circumstances, the fracturing mandrel is connected to an expansion mandrel for further enlarging the hole. Also there can be a carrier ring of the same diameter as the casing to allow for easy field installation. As the assembly is driven into the vault, the components are disassembled thus allowing for the removal of the bursting ram in limited space.
An alternate embodiment, where there is no pulling force applied, entails a centering head that removably covers the front opening of the fracturing mandrel. The centering head is disassembled, which then in turn allows access to the interior for disassembling the bursting ram.